Carby won't idle down

Doctor Rick · Apr 19, 2015

OK, I spent all weekend getting the red belly ready for the Sequim Irrigation Festival Parade.http://www.irrigationfestival.com/events/grand-parade.html

Replaced the plugs and points and what a difference. But the idle won't dial down below about 600, even with the screw turned all the way out.
It runs fine, but I wonder why I can't dial it down.

Late '51 w side dist.

Royse · Apr 20, 2015

Will it idle down if you run the carb to governor linkage by hand?
If not you may want to pull the carb and check the throttle butterfly
to make sure it is on right side up and not binding so it can close fully.

Dean · Apr 20, 2015

Most vintage Ford tractor engines will not idle down to 400 RPM due to air leakage past worn throttle shafts and/or carburetor castings.

If the idle mixture screw is ineffective (or nearly so) in controlling engine idle mixture, air is leaking past the throttle shaft. VERY common.

Dean

old · Apr 20, 2015

Have you tried to back off the throttle stop screw on the carb linkage?? It maybe set for to high an RPM and all the needles adjustments on the carb will not do any thing if that is set for higher RPMs

jon · Apr 20, 2015

Most vintage Ford tractor engines will not idle down to 400 RPM due to air leakage past worn throttle shafts and/or carburetor castings.

Are the common rebuild kits coming with the correct bushings & shafts to cure this?

Royse · Apr 20, 2015

(quoted from post at 21:26:47 04/20/15)

Most vintage Ford tractor engines will not idle down to 400 RPM due to air leakage past worn throttle shafts and/or carburetor castings.

Click to expand...

Are the common rebuild kits coming with the correct bushings & shafts to cure this?

The comprehensive kit sold here on YT comes with shafts and
seals which is normally enough to seal it. It does not come with
bushings. If your casting is worn to the point that it needs a
bushing you would have to buy those separate.

jon · Apr 20, 2015

The comprehensive kit sold here on YT comes with shafts and
seals which is normally enough to seal it. It does not come with
bushings. If your casting is worn to the point that it needs a
bushing you would have to buy those separate.

Royce, does the shaft usually wear before the bushing?
I've (luckily) never had to go that deep on working on a carb.
Maybe I needed to though!

Royse · Apr 20, 2015

(quoted from post at 22:13:23 04/20/15)

The comprehensive kit sold here on YT comes with shafts and
seals which is normally enough to seal it. It does not come with
bushings. If your casting is worn to the point that it needs a
bushing you would have to buy those separate.

Click to expand...

Royce, does the shaft usually wear before the bushing?
I've (luckily) never had to go that deep on working on a carb.
Maybe I needed to though!

Usually, yes. If a leak around the shaft is the issue, a new shaft,
the seal that goes around it and a new retainer (all included in
that comprehensive kit) is all that you would normally need.
The castings do wear out and there are bushings to repair them.

Carby won't idle down

Doctor Rick

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Royse

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Dean

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old

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jon

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Royse

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jon

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Royse

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